This research measured individual and collective tactical performance in a series of engagement simulation exercises against novice opponents and with the same mission and terrain. The effects of engagement simulation training have been difficult to measure since training normally has been conducted with varying missions and terrain against a constantly improving opponent. The results of this research indicate that collective tactical performance is improved by repeated engagement simulation exercises. In the specific conditions tested, rifle squad members defending against a series of 15 rifle platoons in a movement-to-contact mission tended to suffer increased casualties when they caused more casualties. Squad members varied considerably among each other in terms of casualties produced. The squad collectively improved over time in their rate of producing enemy casualties, but did not improve in avoiding enemy fire. The squad collectively inflicted more casualties from some defensive positions than would be expected by chance.